Recovery of Soluble Salts From Aqueous Solutions

ABSTRACT

The invention allows the formation of insoluble chemical compounds in a liquid medium by way of physical stimuli. Highly soluble salts are transformed into insoluble compounds so that they can be separated from aqueous solution to obtain a benefit from both the separated salts and the purified residual liquid.

This application claims the benefit of Chilean Application No. 2879-2008 filed Sep. 26, 2008, the content of which is herein incorporated by reference.

FIELD OF APPLICATION

The field of application of the present invention is the recovery of soluble salts by turning them insoluble through chemical, electric and magnetic processes.

DESCRIPTION OF THE PRIOR ART

There are many processes in the state of the art where chemical reactions result in insoluble products. Other reactions, however, form soluble salts, reason by which they cannot be separated from the aqueous solution.

The present invention solves this technical problem by taking all soluble salts from an aqueous solution and forcing them to form insoluble compounds.

Examples of processes forming insoluble salts are found in the state of the art as follows:

JP2004255627 discloses a process of salt insolubilization as a pre-treatment to prevent membranes from fauling by reverse osmosis. This process does not use any magnetic field nor frequency and cannot insolubilize chlorides or sulphates.

U.S. Pat. No. 5,858,249 discloses a process of insolubilization of ionic species in a kind of electrolytic cell that works as electro-coagulation to form insolubles with salts inherently contained in the (aqueous solution, and the addition of ions of the sacrificial electrode. This process cannot precipitate chlorides or sulphates.

CN 1131127 se discloses a process of insolubilization of salts contained in an aqueous solution by adding chemical reagents, such as phosphate salts and barium salts. The precipitate solutions are separated by filtering, the aqueous solution, in this case water, ending up with a low salt content. This process does not apply electric, magnetic or frequency fields and cannot form compounds.

SUMMARY OF THE INVENTION

The present invention comprises a procedure for forming insoluble chemical compounds in a liquid medium by way of physical stimuli. The compounds thus formed can be inorganic or organic, simple or complex. The technical problem solved by the present invention is that of transforming highly soluble salts into insoluble compounds so that thy may be separated from the aqueous solution to obtain a benefit from both the separated salts and the purified residual liquid.

In a single phase or reactor take place reactive mechanisms and physical changes, as is the initial precipitation of compounds that act as nuclei for subsequent nucleation and absorption mechanisms of other species formed. The formation of these first precipitates is due to the action of an electric and magnetic field applied by way of an ultra-filtered electric current transmitted through electrodes, in addition to the ionic contribution by one of the electrodes acting as a sacrificial one.

Then, a second ionic contribution is added, usually aluminum, calcium, iron, lead or tin to form new compounds with the salts contained in the aqueous solution. With this, the size of the initially formed nuclei is increased by these new compounds and at this stage the absorption of other non-complex salts formed takes place.

The different compounds are formed by selectivity of the processes that are achieved by applying electromagnetic wave frequency in the radio wave spectrum at 1 KHz to 2 MHz frequencies, an electromagnetic wave generator having different geometry and frequency.

The possible fields of application for this technique, among others, are:

-   -   seawater desalinization, chloride and sulphate precipitation.     -   Removal of salts from acid water from mining operations.     -   Precipitation of salts from mining PLS solutions.     -   Potable water treatment, precipitation of chlorides and         sulphates.     -   Boiler water treatment and cooling, removal of sulphates and         chlorides.     -   Irrigation water treatment, chloride and sulphate precipitation.     -   Irrigation water treatment, phosphate and nitrate precipitation.     -   Sewage treatment, precipitation of chlorides, sulphates and         phosphates.     -   Sewage treatment, precipitation of nitrates and nitrites.     -   Insolubilization of salts in processes for producing drugs and         chemical reagents in general.     -   Precipitation of salts as pre-treatment for ultra-filtering and         reverse osmosis processes.

Although these examples might be the ones most known, many other processes may make use of the advantages of being able to insolubilize regularly soluble salts and thus optimize the performance and/or purity of the products obtained. This way, if a process would use part or the entire technology of the present invention, it would fall within the scope of the present invention.

This technology employs ultra-filtered continuous current, with a variable sinusoidal-type wave geometry, damped sawtooth pulse, square wave pulse and an electromagnetic wave signal of the radio spectrum, which are applied through a couple of electrodes. All this, combined, is able to boost the precipitation reactions.

In addition, there must be a preferential pH range for said precipitation, which must be between pH 4 and pH 12. However, if the process is carried out at any of the ranges of the pH scale, good results will be obtained. Subsequently, there is an isokinetic coagulation stage of the precipitated particles, wherein this coagulation is electrically assisted. The voltage applied, corresponding to electric and magnetic fields, is also within a range, which must be between one and one hundred volts, whereas the current's intensity employed must be between 10 mA and 3 A. As mentioned above, the voltage and the electromagnetic signal are applied through electrodes that are submerged in the solution to be treated. The material used to construct said electrodes varies, depending on the quality of the water. These materials may be: lead, platinum, aluminum, copper, coal, gold, tin, zinc, iron, titanium, boron, nickel or diamond.

The entire procedure to form insolubles is done in a single device, which is comprised of different elements, namely:

-   -   A reactor containing 1 pair of electrodes having a different         configuration and made of a different material, inserted by a         side of the reactor, one opposite the other, connected to a         power supply and a magnetic induction source, which is outside         of the device.     -   A second pair of electrodes having a different configuration and         made of a different construction material, inserted within the         reactor, one opposite the other and adjacent to the first pair         of electrodes, connected to a frequency generator that is         located outside of the reactor.     -   A spiral-shaped conducting element that is located outside of         the reactor and connected to a power supply and a magnetic         induction source, where, through this element flows current that         generate specific magnetic fields.     -   Injection of photonized air produced by a blowing pump and a         photon emitter that enters the reactor through a capillary         located next to the electrode that is connected to the negative         pole of the power supply, in order for the capillary to be as         close as to the reactor's bottom as possible.     -   An electric and magnetic field generator and an adjustable         frequency generator located outside of the reactor.     -   A speed-adjustable paddle stirring means that is located at the         center of the reactor.

In addition, the execution of all these processes may be carried out in other facilities with more than one device.

The process to form precipitates includes specific pressure and temperature values, which are within a range of 1 to 10 bars and 0 to 90° C. ranges, respectively. This is due to the fact that the precipitation process is based on the concentration, which implies a displacement of the balance constant, which allows oversaturation. The effect of temperature affects the reaction's kinetics, increasing the precipitation process, because molecular collisions accelerate and, as a result thereof, the kinetic constant rises. The application of external pressure causes leads to the same result. A clear example thereof is jarosite precipitation, which formation is not possible under normal conditions, reason by which the application of these variables is required.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the components of the inventions and its connections therewith.

DETAILED DESCRIPTION OF THE INVENTION

The process is carried out in a single step, in a device comprising a reactor (1) having a pair of electrodes (2 and 3) connected to a power supply and a source magnetic induction (4), and a second pair of electrodes (5 and 6) connected to a frequency generator (7). A current of pressurized photonized air containing ozone and oxidant-free radicals enters the reactor from an air pump (9) that circulates air through a photon generator (10). Also, a spiral-shaped conducting element (11) surrounds the exterior of the reactor, through which circulates a current that generates specific magnetic fields. Said element is connected to a power supply and source of magnetic induction (4) that generates current. Everything is stirred with a mechanical or magnetic stirring device (8), and a chemical reagent adding the ions that are not present in the aqueous solution and that are necessary to complete the desired insoluble compounds is added. In most cases, the calcium and hydroxyl ions are insufficient, reason by which line is preferably used as a single reagent.

Example 1

If we take, for example, the application of the sea water desalinization process, the mechanism employed is as follows:

Firstly, an air mixture that passes through photons is applied, and then it is directly applied on the sea water. The resulting reactions are:

${\frac{1}{2}O_{2}} + {H_{2}{O\overset{K_{1},{{hv} + {\Delta \; E^{0}}}}{}2}\; {{OH}^{0}\overset{K_{2},{\Delta \; E^{0}}}{}2}\; {OH}^{-}}$

The reaction above is applied until pH>9.8 units. The electric field is applied through aluminum electrodes causing a second electrolytic reaction that is:

${{Al}{\text{?}\overset{K}{}{Al}^{+ 8}}} + {3\; e^{-}}$ ?indicates text missing or illegible when filed

The aluminum reacts with the OH ions forming the first nucleation based in the following reaction:

${Al}^{+ 2} + {3\; {{OH}^{-}\overset{K}{}{{Al}({OH})}_{2}}}$

Once the aluminum hydroxide nuclei are formed, the calcium hydroxide is dosed and a 1.8 MHz length wave radio frequency is applied, and then the following sulphate, chloride and phosphate precipitation reaction is formed:

$\mspace{20mu} {{6\; {Ca}^{+ 2}} + {3\; {SO}_{4}^{- 2}} + {2\; {{{Al}({OH})}_{2}\overset{K,{\Delta \; E},\phi,{RF}}{}{Ca}_{6}}{{Al}_{2}\left( {SO}_{4} \right)}_{3}({OH})_{12}}}$ ${4\; {Ca}^{+ 2}} + {2\; {Cl}^{-}} + {2\; {{Al}({OH})}_{2}} + {3\; H_{2}O} + {\frac{3}{2}{O_{2}\overset{K,{\Delta \; E},\phi,{RF}}{}{Ca}_{4}}{Al}_{2}{{Cl}_{2}({OH})}_{12}}$ $\mspace{20mu} {{5\; {Ca}^{+ 2}} + {3\; {PO}_{4}^{- 3}} + {{{OH}^{-}\overset{K,{\Delta \; E},\phi,{RF}}{}{{Ca}_{5}\left( {PO}_{4} \right)}_{3}}{OH}}}$

Ionic copper may be alternatively formed by applying, along with the formation of ionic aluminum, in a pair of copper electrodes to firstly form the reaction:

${{Cu}^{0}\overset{K}{}{Cu}^{+ 2}} + {2\; e^{-}}$

The nitrate is captured from the medium based on the following reactions:

${Cu}^{+ 2} + {2\; {{NO}_{3}^{-}\overset{K}{}{{Cu}\left( {NO}_{3} \right)}_{2}}}$ ${Cu}^{+ 2} + {{OH}^{-}\overset{K}{}{{Cu}({OH})}_{2}}$

With the above, and in the previous means of radio frequency and field, the following reaction is formed:

${4\; {Cu}^{+ 2}} + {2\; {NO}_{3}^{-}} + {2\; {{OH}^{-}\overset{K,{RF},{\Delta \; E},\phi}{}{{Cu}\left( {NO}_{3} \right)}_{2}}3\; {{Cu}({OH})}_{2}}$

The, chlorides, sulphates, phosphates and nitrates have been precipitated. The removal of anions brings with it the removal of aluminum, copper and calcium. Each precipitate formed has a great capacity to absorb heavy metals.

These insolubles as formed are generally micro-precipitates that must grow. In order to boost growth, flocculation is caused by adding a polymer and then by separating by settling and then by filtering.

The following chart shows the operational conditions and dosage at which the experience was carried out using sea water from San Antonio, 5th Region.

Order Description Value Unit 1 Aluminum Intensity 5 amperes 2 Copper Intensity 0.1 amperes 3 Voltage 0.62 Volts 4 Time 60 minutes 5 Al mass 1,679 mg 6 Cu mass 119 mg 7 Air dosage 1.5 L/min 8 Line dosage 17.5 g/L 9 Radio Frequency 1.5 MHz 10 Pulse applied damped Saw wave 11 Sample volume 0.75 L 12 Alumina dosage 4.85 g/L 13 Total energy 3.1 Watts-h 4.13 KW-h/m³

The following chart shows the efficiencies reached when removing the salts from the seawater. The chart contains a raw column, which indicates the quality of seawater. The treated column shows the value reached following sand and coal flocculation and filtering. The % removal column shows the validity obtained.

Element Unit Raw Treated % Removal Chlorides mg/L 19,500 2,650 86.4% Sulphates mg/L 2,850 327 88.5% Nitrates mg/L 220 25 88.6% Phosphates mg/L 78 5 93.6%

Example 2

Another example of the application of salt precipitation is the insolubilization of sulphates in mining waters.

To this effect, a water sample, taken at Collahuasi Mine, with an initial content of 5,200 mg/L of sulphates.

The compound employed was precipitation, just as that of sodium jarosite. M[Al₃(SO₄)₂(OH)₆]

The M element may be sodium or potassium. To this effect, the following mechanism was employed.

Firstly, an air mixture passing through photons is applied, and then it is directly applied on seawater. The resulting reactions are:

${\frac{1}{2}O_{2}} + {H_{2}{O\overset{K_{1},{{hv} + {\Delta \; E^{0}}}}{}2}\; {{OH}^{0}\overset{K_{2},{\Delta \; E^{0}}}{}2}\; {OH}^{-}}$

The reaction above is applied until pH>9.8 units. The electric field is applied through aluminum electrodes causing a second electrolytic reaction that is:

${{Al}{\text{?}\overset{K}{}{Al}}\text{?}} + {3\; e^{-}}$ ?indicates text missing or illegible when filed

The aluminum reacts with the OH ions forming the first nucleation based in the following reaction:

${{Al}\text{?}} + {3\; {{OH}^{-}\overset{K}{}{{Al}({OH})}}\text{?}}$ ?indicates text missing or illegible when filed

In the balance aluminum hydroxide nuclei are formed, and then they precipitate as jarosite in the medium with radio frequency and electric field.

$M^{+} + {2\; {{Al}({OH})}\text{?}} + {2\; {SO}_{4}^{=}} + {{Al}{\text{?}\overset{K,{RF},{\Delta \; E},\phi}{}{M\left\lbrack {{{Al}_{3}\left( {SO}_{4} \right)}_{2}({OH})_{6}} \right\rbrack}}}$ ?indicates text missing or illegible when filed

The operational conditions are:

Order Description Value Unit 1 Aluminum Intensity 6 amperes 2 Voltage 1.18 Volts 3 Time 55 minutes 4 Al mass 1,847 mg 5 Air dosage 1.5 L/min 6 Radio Frequency 1.5 MHz 7 Pulse applied damped Saw wave 8 Sample volume 0.75 L 9 Total energy 6.49 Watts-h 8.65 KW-h/m³ The results obtained are:

Element Unit Raw Treated % Removal Sulphates mg/L 6,820 870 87.2%

This way, different insoluble elements with which salts mat be reduced may be configured. 

1. A device to form insoluble chemical compounds from salts containing the aqueous solution to be treated, comprising a Reactor comprising: a) a pair of electrodes having a different configuration and made of a different material, inserted by a side of the reactor, one opposite the other, connected to a power supply and a magnetic induction source, which is outside of the device; b) A second pair of electrodes having a different configuration and made of a different construction material, inserted within the reactor, one opposite the other and adjacent to the first pair of electrodes, connected to a frequency generator that is located outside of the reactor; c) A spiral-shaped conducting element that is located outside of the reactor and connected to a power supply and a magnetic induction source, where, through this element flows current that generate specific magnetic fields; d) Injection of photonized air produced by a blowing pump and a photon emitter that enters the reactor through a capillary located next to the electrode that is connected to the negative pole of the power supply, in order for the capillary to be as close as to the reactor's bottom as possible; e) An electric and magnetic field generator and an adjustable frequency generator, located outside of the reactor; and f) A speed-adjustable paddle stirring means that is located at the center of the reactor.
 2. A device to form insoluble chemical compounds, wherein the power supply and the source of magnetic induction causes the application of an ultra-filtered continuous current voltage, with a variable sinusoidal-type wave geometry, damped sawtooth pulse, square wave pulse and an electromagnetic wave signal of the radio spectrum, which are applied through pairs of electrodes that, in combination or individually, are able to boost the precipitation reactions, wherein these electrodes are contained in a device that connects them to electric and magnetic field generators and to frequency generators.
 3. The device to form insoluble chemical compounds of claim 1, wherein the reactions taking place within the reactor are within a whole range of the pH scale, preferably between pH 4 and pH 12, depending on the balance constant, followed by an electrically assisted kinetic coagulation stage of the precipitated particles.
 4. The device to form insoluble chemical compounds of claim 1, wherein the voltages applied correspond to electric and magnetic fields having a voltage between one and one hundred volts, and a current intensity between 10 mA and 3 A.
 5. The device to form insoluble chemical compounds of claim 1, wherein the electric and magnetic fields and/or frequencies are transmitted through different kinds of pairs of electrodes that are made of one of the following elements: lead, platinum, aluminum, copper, coal, gold, tin, zinc, iron, titanium, boron, nickel, diamond; this first electrode working in tandem with another electrode of the same element, with other electrodes as mentioned above or alloys thereof.
 6. The device to form insoluble chemical compounds of claim 1, wherein the execution of all of the processes inside the reactor are within a temperature range between 0 and 90° C. and within a pressure range between 1 and 10 bars.
 7. A method for using a device to form insoluble chemical compounds comprising the steps of: a) providing a leaching reactor with a pair of electrodes having a different configuration and made of a different material, inserted by a side of the reactor, one opposite the other; b) providing a second pair of electrodes having a different configuration and made of a different construction material, inserted within the reactor, one opposite the other and adjacent to the first pair of electrodes; c) providing a power supply located outside of the reactor; d) providing a frequency generator located outside of the reactor; e) Providing a photonized air injection system; f) Providing an air pump and a capillary located adjacent to the electrode that is connected to the negative pole of the power supply; g) Providing an electric and magnetic field generator and an adjustable frequency generator located outside of the reactor; h) Providing a speed-adjustable paddle stirring means located at the center of the reactor; i) Providing a spiral-shaped conducting element surrounding the outside of the reactor; j) Introducing into the reactor a solution having insoluble chemical compounds; k) Injecting, by employing an air pump, the photonized air injector and the capillary, air containing ozone and free radicals into the reactor; l) Simultaneously, applying, by employing the frequency generator and a pair of electrodes, a frequency or a electromagnetic signal of the radio spectrum to a solution containing insoluble chemical compounds inside the reactor; m) Simultaneously, applying, by employing the power supply and another pair of electrodes, an electric voltage, consisting of pulsating continuous current, to the solution containing insoluble chemical compounds inside the reactor; n) Simultaneously, applying, by using the spiral-shaped conducting element, specific magnetic fields; o) Simultaneously, stirring, by employing the paddle stirring means, the solution containing insoluble chemical compounds inside the reactor; p) Simultaneously, adding a chemical reagent adding ions that are not present in the aqueous solution and that are necessary to complete the desired insoluble compounds, preferably lime; and q) Adding a second contribution of ions, such as aluminum, calcium, iron, lead or tin, to form new compounds with the salts contained in the aqueous solution. 